1. Field of the Invention
The present invention relates to a steering damper device for a saddle riding vehicle.
2. Discussion of the Background
A known steering damper device for a saddle riding type vehicle having a steering system rotatably supported on a head pipe of a vehicle body frame includes a tubular damper disposed immediately before the head pipe so as to extend therealong. The tubular damper has a lower end portion oscillatably mounted on a bottom bridge and an upper end portion oscillatably mounted on the head pipe. The tubular damper is adapted to extend or contract along the head pipe when the steering system is turned clockwise or counterclockwise from the position of a steering angle of 0 degrees (a vehicle's straight-ahead position) (see, for example, Japanese Patent No. 4206353). According to the foregoing arrangement, disposing the tubular damper immediately before the head pipe so as to extend therealong allows a damping force to be efficiently given to rotation of the steering system.
Another known arrangement has a tubular damper disposed on one side of a down frame that extends downwardly from a head pipe, so as to extend therealong adjacent thereof. The tubular damper has an intermediate portion oscillatably journaled on the down frame and an upper end portion connected to a bottom bridge via a linkage mechanism (see, for example, Japanese Patent Laid-Open No. 2009-113679).
The former arrangement described above, in which the tubular damper is disposed forwardly of the head pipe, poses a problem in that it is difficult to allow a clearance when a vehicle component, such as a headlight, is disposed forwardly of the head pipe.
On the other hand, the latter arrangement described above, in which the tubular damper is disposed sideways the down frame, poses a problem in that a difference is involved in the damping force given during clockwise or counterclockwise rotation of the steering system between the clockwise and counterclockwise rotation, which produces a change in damping characteristics.